Supercharger

Abstract

A supercharger (TC) is provided with a support ring (26) and a drive ring (27) that rotates around the support ring (26). The drive ring (27) includes an inner peripheral surface (27a) in contact with the support ring (26), and a first end surface (27d) and a second end surface (27e) in the axial direction. The first end surface (27d) is disposed in the vicinity of the annular flow path in which the plurality of nozzle blades are disposed with respect to the second end surface (27e) in the axial direction. The drive ring includes a first R-shape (R1) connecting an inner peripheral surface (27a) to a first end surface (27d) in a cross section along the axis.

Description

TECHNICAL FIELD

[0001] The present disclosure relates to a supercharger. This application claims the benefit of priority of Japanese Patent Application No. 2023-192304 filed on November 10, 2023, the contents of which are incorporated herein. BACKGROUND

[0002] A supercharger sometimes has a mechanism that adjusts the cross-sectional area of a flow path of a turbine. For example, Patent Literature 1 discloses a supercharger that has a nozzle drive mechanism. The nozzle drive mechanism adjusts the width of a flow path inside a turbine housing. The flow path has a ring shape around a central axis of a turbine wheel. The nozzle drive mechanism has a plurality of nozzle vanes. The plurality of nozzle vanes is arranged along a circumferential direction in the ring-shaped flow path. Each nozzle vane rotates around an axis portion that is parallel to the central axis of the turbine wheel. The width of the flow path is adjusted by simultaneously rotating the plurality of nozzle vanes. The nozzle drive mechanism has a drive ring that simultaneously rotates the plurality of nozzle vanes. The drive ring is slidingly rotated around a drive ring support.

[0003] PRIOR ART DOCUMENTS

[0004] PATENT LITERATURE

[0005] Patent Literature 1: Japanese Patent Application Publication No. 2020-165374 SUMMARY

[0006] PROBLEMS TO BE SOLVED BY THE INVENTION

[0007] The above-described mechanism can be worn by the rotation of the drive ring.

[0008] An object of the present disclosure is to provide a supercharger that can reduce wear caused by the rotation of a drive ring.

[0009] MEANS FOR SOLVING THE PROBLEMS

[0010] To solve the above-described problems, a supercharger according to an aspect of the present disclosure includes a turbine wheel, a housing that houses the turbine wheel and includes a ring-shaped flow path formed on a radially outer side of the turbine wheel, a plurality of rotatable nozzle vanes arranged in the ring-shaped flow path along a circumferential direction of the turbine wheel, a support ring having a ring shape around an axis of the turbine wheel and housed in the housing, and a drive ring having a ring shape around the axis of the turbine wheel and rotating around the support ring to simultaneously rotate the plurality of rotatable nozzle vanes, the drive ring including an inner peripheral surface that contacts the support ring, and a first end surface and a second end surface in an axis direction of the turbine wheel, the first end surface being arranged in the vicinity of the ring-shaped flow path with respect to the second end surface in the axis direction, the drive ring including a first R shape that connects the inner peripheral surface to the first end surface in a cross section along the axis of the turbine wheel.

[0011] The first R shape can be connected to the inner circumferential surface by a tangent line of the first R shape in the above-mentioned cross section.

[0012] The radius of curvature of the first R shape can be 6% or more of the width of the drive ring in the axial direction in the above-mentioned cross section.

[0013] The radius of curvature of the first R shape can be 45% or less of the width of the drive ring in the above-mentioned cross section.

[0014] The drive ring can include a second R shape connecting the inner circumferential surface to the second end surface in the above-mentioned cross section.

[0015] The support ring can include a plurality of protrusions protruding in the axial direction and in contact with the inner circumferential surface of the drive ring, each of the plurality of protrusions can include an outer surface in contact with the inner circumferential surface of the drive ring, and a third end surface and a fourth end surface in the circumferential direction, and each of the plurality of protrusions can include a third R shape connecting the outer surface to the third end surface and a fourth R shape connecting the outer surface to the fourth end surface in a cross section perpendicular to the axis of the turbine wheel.

[0016] Alternatively, each of the plurality of protrusions can include a third chamfer connecting the outer surface to the third end surface and a fourth chamfer connecting the outer surface to the fourth end surface in a cross section perpendicular to the axis of the turbine wheel.

[0017] Effects of the Invention

[0018] According to the present disclosure, it is possible to reduce wear caused by rotation of the drive ring. BRIEF DESCRIPTION OF DRAWINGS

[0019] Figure 1 is a schematic cross-sectional view of a turbocharger according to an embodiment.

[0020] Figure 2 is a schematic exploded perspective view of a nozzle drive mechanism.

[0021] Figure 3 is a schematic perspective view of the nozzle drive mechanism after assembly.

[0022] Figure 4 is a schematic perspective view of a drive ring and a first protrusion taken along Figure 2 a-a line and b-b line in FIG. 6.

[0023] Figure 5 is a graph showing the relationship between the size of the R shape and the surface pressure ratio.

[0024] Figure 6A is a schematic cross-sectional view of a drive ring after press working and before barrel polishing. Figure 6B is a schematic cross-sectional view of a drive ring after barrel polishing.

[0025] Figure 7A is an example of a cross-sectional view of the first protrusion taken along the c-c line in Figure 2 Figure 7B is another example of a cross-sectional view of the first protrusion taken along the c-c line in Figure 2 DETAILED DESCRIPTION

[0026] Hereinafter, an embodiment of the present disclosure will be described in detail with reference to the drawings. The specific dimensions, materials, numerical values, and the like shown in the embodiment are merely examples for easy understanding, and do not limit the present disclosure unless specifically described. Furthermore, in the present specification and drawings, elements having substantially the same function, structure, and the like are designated by the same reference numerals, and thus repetitive explanation is omitted. In addition, elements having no direct relation to the present disclosure are omitted from the illustration.

[0027] Figure 1 is a schematic cross-sectional view of a supercharger TC of the embodiment. The supercharger TC is provided with a housing 1, a shaft 2, a turbine impeller 3, and a compressor impeller 4.

[0028] As described later, the turbine impeller 3 and the compressor impeller 4 rotate integrally with the shaft 2. Therefore, in the present disclosure, the axial direction, the radial direction, and the circumferential direction of the shaft 2, the turbine impeller 3, and the compressor impeller 4 can be simply referred to as "axial direction", "radial direction", and "circumferential direction", respectively, unless otherwise indicated. In addition, in the present disclosure, the axis of the shaft 2, the turbine impeller 3, and the compressor impeller 4 can be simply referred to as "axis", unless otherwise indicated.

[0029] The housing 1 includes a bearing housing 5, a turbine housing 6, and a compressor housing 7. In the axial direction, one end portion of the bearing housing 5 is connected to the turbine housing 6. In the axial direction, the other end portion of the bearing housing 5 is connected to the compressor housing 7.

[0030] The bearing housing 5 includes a bearing hole 5a. The bearing hole 5a extends in the axial direction within the bearing housing 5. The bearing hole 5a houses a bearing B. The bearing B rotatably supports the shaft 2. In the present embodiment, as the bearing B, a semi-floating bearing is used. In other embodiments, as the bearing B, a full-floating bearing or other radial bearings such as a rolling bearing can also be used.

[0031] In the axial direction, the turbine impeller 3 is provided at a first end portion of the shaft 2. The turbine impeller 3 rotates integrally with the shaft 2. The turbine housing 6 rotatably houses the turbine impeller 3. In the axial direction, the compressor impeller 4 is provided at a second end portion of the shaft 2 on the side opposite to the first end portion. The compressor impeller 4 rotates integrally with the shaft 2. The compressor housing 7 rotatably houses the compressor impeller 4. ​​

[0032] The compressor housing 7 includes an intake port 71 at an end on the side opposite the bearing housing 5 in the axial direction. The intake port 71 is connected to an air cleaner, not shown.

[0033] The bearing housing 5 and the compressor housing 7 define a diffusion flow path 72 therebetween. The diffusion flow path 72 has a ring shape. The diffusion flow path 72 is located radially outward of the compressor impeller 4. The diffusion flow path 72 is in fluid communication with the intake port 71 via the compressor impeller 4.

[0034] The compressor housing 7 includes a compressor scroll flow path 73. The compressor scroll flow path 73 is located radially outward of the diffusion flow path 72. The compressor scroll flow path 73 is connected to the diffusion flow path 72. In addition, the compressor scroll flow path 73 is in fluid communication with an intake port of an engine, not shown.

[0035] When the compressor impeller 4 rotates, air is drawn into the compressor housing 7 from the intake port 71. The air is accelerated by centrifugal force and pressurized during passage through the compressor impeller 4. The air is further pressurized as it passes through the diffusion flow path 72 and the compressor scroll flow path 73. The pressurized air is discharged from a discharge port, not shown, and is directed to the intake port of the engine. In the supercharger TC, the portion including the compressor impeller 4 and the compressor housing 7 functions as a centrifugal compressor C.

[0036] The turbine housing 6 includes a discharge port 61 at an end on the side opposite the bearing housing 5 in the axial direction. The discharge port 61 is connected to an exhaust purification device, not shown.

[0037] The turbine housing 6 includes a connection flow path (ring flow path) 62. The connection flow path 62 has a ring shape. The connection flow path 62 is located radially outward of the turbine impeller 3. The connection flow path 62 is in fluid communication with the discharge port 61 via the turbine impeller 3. The nozzle driving mechanism 20 is provided in the connection flow path 62. Details of the nozzle driving mechanism 20 will be described later.

[0038] The turbine housing 6 includes a turbine scroll flow path 63. The turbine scroll flow path 63 is located radially outward of the connection flow path 62. The turbine scroll flow path 63 is connected to the connection flow path 62. In addition, the turbine scroll flow path 63 is in fluid communication with a gas flow inlet, not shown. The gas flow inlet receives exhaust gas discharged from an exhaust manifold of an engine, not shown.

[0039] The exhaust gas is guided from the gas inflow port to the turbine scroll flow path 63, and further guided to the outflow port 61 via the connecting flow path 62 and the turbine impeller 3. The exhaust gas rotates the turbine impeller 3 during passing through the turbine impeller 3. The rotational force of the turbine impeller 3 is transmitted to the compressor impeller 4 via the shaft 2. If the compressor impeller 4 rotates, the air is pressurized as described above. In this way, the pressurized air is guided to the intake port of the engine. In the supercharger TC, the portion including the turbine impeller 3 and the turbine housing 6 functions as a turbine T.

[0040] If the flow rate of the exhaust gas from the engine changes, the rotational speed of the turbine impeller 3, that is, the rotational speed of the compressor impeller 4 changes. Therefore, depending on the operating condition of the engine, the air can not be pressurized as intended in the centrifugal compressor C. The nozzle drive mechanism 20 addresses such a problem.

[0041] The nozzle drive mechanism 20 adjusts the cross-sectional area of the connecting flow path 62. If the cross-sectional area of the connecting flow path 62 changes, the flow rate of the exhaust gas guided to the turbine impeller 3 also changes. Specifically, in a case where the rotational speed of the engine is low and the flow rate of the exhaust gas is low, the nozzle drive mechanism 20 reduces the cross-sectional area of the connecting flow path 62. As a result, the flow rate of the exhaust gas guided to the turbine impeller 3 increases. Therefore, the nozzle drive mechanism 20 can rotate the turbine impeller 3 with the exhaust gas of low flow rate.

[0042] Next, the nozzle drive mechanism 20 will be described in detail.

[0043] Figure 2 is an exploded perspective view of the nozzle drive mechanism 20. The nozzle drive mechanism 20 includes a first plate 21, a plurality of pins 22, a second plate 23, a plurality of nozzle vanes 24, a third plate 25, a support ring 26, a drive ring 27, and a plurality of link plates 28. The nozzle drive mechanism 20 can further include other constituent elements.

[0044] The first plate 21 has a ring shape. Referring to Figure 1 In the present embodiment, the first plate 21 is mounted to the turbine housing 6. The first plate 21 is disposed coaxially with the turbine impeller 3.

[0045] Referring to Figure 2 The first plate 21 includes a plurality of first pin holes 21a disposed separately from each other along the circumferential direction. For example, the plurality of first pin holes 21a are disposed at equal intervals in the circumferential direction. In other embodiments, the plurality of first pin holes 21a can be disposed at different intervals in the circumferential direction. The first pin holes 21a penetrate the first plate 21 in the axial direction. The first ends of the pins 22 are respectively inserted into the first pin holes 21a. Therefore, the number of the first pin holes 21a corresponds to the number of the pins 22.

[0046] The second plate 23 has a ring shape. The second plate 23 is disposed coaxially with the first plate 21. The first plate 21 and the second plate 23 are separated from each other in the axial direction. Referring to Figure 1 , the connecting flow path 62 is demarcated between the first plate 21 and the second plate 23.

[0047] Referring to Figure 2 , the second plate 23 includes a plurality of second pin holes 23a disposed separately from each other along the circumferential direction. For example, the plurality of second pin holes 23a are disposed at equal intervals in the circumferential direction. In other embodiments, the plurality of second pin holes 23a can also be disposed at different intervals in the circumferential direction. The second pin holes 23a penetrate the second plate 23 in the axial direction. The second pin holes 23a are opposed to the first pin holes 21a in the axial direction. The second ends of the pins 22 are respectively inserted into the second pin holes 23a. Thus, the number of the second pin holes 23a corresponds to the number of the pins 22.

[0048] The pins 22 include flanges for positioning the first plate 21 and the second plate 23 in the axial direction, and the distance between the first plate 21 and the second plate 23 is specified by the flanges. In the present embodiment, three pins 22 are used. The number of the pins 22 is not limited thereto, and for example, one, two, or four or more pins 22 can also be used.

[0049] The second plate 23 includes a plurality of first shaft holes 23b disposed separately from each other along the circumferential direction. The plurality of first shaft holes 23b are disposed at equal intervals in the circumferential direction. The first shaft holes 23b penetrate the second plate 23 in the axial direction. For example, the first shaft holes 23b are located radially inward of the second pin holes 23a. The number of the first shaft holes 23b corresponds to the number of the nozzle vanes 24.

[0050] Referring to Figure 1 , the plurality of nozzle vanes 24 are disposed separately from each other along the circumferential direction in the connecting flow path 62. The plurality of nozzle vanes 24 are disposed radially outward of the turbine wheel 3. Referring to Figure 2 , in the present embodiment, eleven nozzle vanes 24 are used. The number of the nozzle vanes 24 is not limited thereto. The nozzle vane 24 includes a vane body 24a and a shaft 24b.

[0051] The vane body 24a is arranged in a gap between the first plate 21 and the second plate 23, that is, the connection flow path 62. The shaft 24b protrudes from the vane body 24a in the axial direction. The shaft 24b is inserted into the first shaft hole 23b of the second plate 23. Thus, a plurality of nozzle vanes 24 are arranged at equal intervals in the circumferential direction. The nozzle vane 24 is rotatably supported by the first shaft hole 23b. The nozzle vane 24 is rotatable about each axis parallel to the axis of the turbine wheel 3. In the present embodiment, the nozzle vane 24 is supported only by the second plate 23. In other embodiments, the nozzle vane 24 can also include another shaft not shown that protrudes in the direction opposite to the shaft 24b and can be supported by the first plate 21 by being inserted into a hole not shown formed in the first plate 21.

[0052] The third plate 25 has a ring shape. The third plate 25 is arranged coaxially with the first plate 21 and the second plate 23. The third plate 25 is arranged on the opposite side of the first plate 21 from the second plate 23 in the axial direction. Referring to Figure 1 For example, the radially outer portion of the third plate 25 is held by the bearing housing 5 and the turbine housing 6.

[0053] Referring to Figure 2 The third plate 25 includes a plurality of protrusions 25a arranged separately from each other in the circumferential direction. For example, the plurality of protrusions 25a are arranged at equal intervals in the circumferential direction. In other embodiments, the plurality of protrusions 25a can also be arranged at different intervals in the circumferential direction. The protrusion 25a protrudes from the inner circumferential surface of the third plate 25 toward the radially inner side. The protrusion 25a includes a third pin hole 25b. The third pin hole 25b penetrates the protrusion 25a in the axial direction. The third pin hole 25b is opposed to the second pin hole 23a in the axial direction. The second end portion of the pin 22 is inserted into the third pin hole 25b. Thus, the number of third pin holes 25b corresponds to the number of pins 22.

[0054] The support ring 26 has a ring shape. The support ring 26 is arranged coaxially with the first plate 21, the second plate 23, and the third plate 25. The support ring 26 is arranged on the opposite side of the second plate 23 from the third plate 25 in the axial direction.

[0055] The support ring 26 includes a plurality of fourth pin holes 26a arranged separately from each other in the circumferential direction. For example, the plurality of fourth pin holes 26a are arranged at equal intervals in the circumferential direction. In other embodiments, the plurality of fourth pin holes 26a can also be arranged at different intervals in the circumferential direction. The fourth pin hole 26a penetrates the support ring 26 in the axial direction. The fourth pin hole 26a is opposed to the third pin hole 25b in the axial direction. The second end portion of the pin 22 is inserted into the fourth pin hole 26a. Thus, the number of fourth pin holes 26a corresponds to the number of pins 22.

[0056] As described above, the pin 22 is inserted into the first pin hole 21a, the second pin hole 23a, the third pin hole 25b, and the fourth pin hole 26a. The first end portion and the second end portion of the pin 22 are fastened.

[0057] Figure 3 is a perspective view of the assembled nozzle driving mechanism 20. When the first end portion and the second end portion of the pin 22 are fastened as described above, the first plate 21, the second plate 23, the third plate 25, and the support ring 26 are fixed to each other by the plurality of pins 22. In addition, referring to Figure 1 As described above, the first plate 21 is mounted to the turbine housing 6, and the radially outer portion of the third plate 25 is held to the bearing housing 5 and the turbine housing 6. Therefore, the first plate 21, the second plate 23, the third plate 25, and the support ring 26 are fixed with respect to the bearing housing 5 and the turbine housing 6.

[0058] Referring to Figure 2 The support ring 26 includes a plurality of first protrusions 26b which are arranged separately from each other in the circumferential direction. For example, the plurality of first protrusions 26b are arranged at different intervals in the circumferential direction. In other embodiments, the plurality of first protrusions 26b can also be arranged at equal intervals in the circumferential direction. The first protrusions 26b protrude from the outer periphery of the support ring 26 in the axial direction opposite to the third plate 25. In the present embodiment, six first protrusions 26b are used. The number of the first protrusions 26b is not limited thereto. The front end of the first protrusion 26b is bent toward the radially outer side. Therefore, the first protrusion 26b has a substantially L-shaped shape.

[0059] The support ring 26 includes a plurality of second protrusions 26c which are arranged separately from each other in the circumferential direction. For example, the plurality of second protrusions 26c are arranged at equal intervals in the circumferential direction. In other embodiments, the plurality of second protrusions 26c can also be arranged at different intervals in the circumferential direction. The second protrusions 26c protrude from the outer peripheral surface of the support ring 26 toward the radially outer side. The second protrusions 26c are arranged at positions different from the first protrusions 26b in the circumferential direction.

[0060] The drive ring 27 has a ring shape. The drive ring 27 is arranged coaxially with the first plate 21, the second plate 23, the third plate 25, and the support ring 26. The drive ring 27 is positioned in the axial direction by the support ring 26. Specifically, the drive ring 27 is arranged in the axial direction between the bent front end of the first protrusion 26b and the second protrusion 26c. Therefore, the movement of the drive ring 27 in the axial direction is restricted by the bent front end of the first protrusion 26b and the second protrusion 26c. The inner peripheral surface 27a of the drive ring 27 is in contact with the outer surface of the first protrusion 26b (details will be described later).

[0061] The front end of the shaft 24b of the nozzle vane 24 protrudes in the axial direction from the first shaft hole 23b of the second plate 23, and further inserted into the second shaft hole 28a of the link plate 28.

[0062] Reference Figure 3 As described above, the front end of the shaft 24b of the nozzle blade 24 protrudes from the second shaft hole 28a of the connecting rod plate 28 and is then fastened. In this way, the nozzle blade 24 and the connecting rod plate 28 are fixed to each other. The number of connecting rod plates 28 corresponds to the number of nozzle blades 24.

[0063] Reference Figure 2 The connecting rod plate 28 has an elongated shape. In this embodiment, the connecting rod plate 28 has a generally pear-shaped shape. A plurality of connecting rod plates 28 are arranged circumferentially separated from each other inside the drive ring 27. The aforementioned second shaft hole 28a is formed at the radially inner end of the connecting rod plate 28.

[0064] A plurality of first grooves 27b are formed on the inner circumferential surface 27a of the drive ring 27, arranged circumferentially apart from each other. The first grooves 27b are recessed from the inner circumferential surface 27a toward the radially outward side. (Refer to...) Figure 3 The radially outer end of the connecting rod plate 28 is inserted into the first slot 27b. The number of first slots 27b is equal to the number of connecting rod plates 28. The multiple first slots 27b are arranged at equal intervals in the circumferential direction. Therefore, the connecting rod plates 28 are also arranged at equal intervals in the circumferential direction.

[0065] Reference Figure 2 A single second groove 27c is formed on the inner circumferential surface 27a of the drive ring 27. The second groove 27c has a shape substantially the same as the first groove 27b. The second groove 27c is formed between a set of consecutive first grooves 27b.

[0066] Reference Figure 3 The second groove 27c is subjected to a circumferential (tangential) force from the actuator via a connecting rod (not shown). Therefore, the drive ring 27 is subjected to a force relative to the bearing housing 5 and the turbine housing 6 (in... Figure 3 (Not shown in the diagram) The plurality of first protrusions 26b of the fixed support ring 26 rotate circumferentially. When the drive ring 27 rotates, each connecting rod plate 28 and the corresponding shaft 24b rotate about the axis of the shaft 24b. Therefore, referring to... Figure 2 Multiple blades 24a connected to shaft 24b rotate simultaneously, adjusting the cross-sectional area of ​​the connecting flow path 62.

[0067] As described above, the drive ring 27 rotates about a plurality of first protrusions 26b. Therefore, the inner circumferential surface 27a of the drive ring 27 slides relative to the outer surface of the first protrusions 26b. In this disclosure, the drive ring 27 is configured to reduce wear associated with sliding.

[0068] Next, the drive ring 27 and the first protrusion 26b will be described in detail.

[0069] Figure 4 It includes along Figure 2A rough three-dimensional view of the assembled cross-sections of the drive ring 27 and the first protrusion 26b, obtained by cutting lines aa and bb. It should be noted that... Figure 2 In the middle, the drive ring 27 and the first protrusion 26b are disassembled, but Figure 4 This shows the cross-section of the assembled drive ring 27 and the first protrusion 26b. Figure 4 This represents the cross section along the axis of turbine impeller 3.

[0070] The first protrusion 26b includes an outer surface 26d. The outer surface 26d faces radially outward.

[0071] In addition to the inner circumferential surface 27a mentioned above, the drive ring 27 also includes a first end surface 27d, a second end surface 27e, and an outer circumferential surface 27f.

[0072] The inner circumferential surface 27a and the outer circumferential surface 27f are located in opposite positions radially. The inner circumferential surface 27a faces radially inward. The outer circumferential surface 27f faces radially outward. In this embodiment, in Figure 4 In the cross-section, the inner circumferential surface 27a and the outer circumferential surface 27f each have a straight line shape.

[0073] The first end face 27d and the second end face 27e are located opposite to each other in the axial direction. The first end face 27d and the second end face 27e are perpendicular to the axial direction. The first end face 27d is disposed relative to the second end face 27e in the connecting flow path 62 (in...). Figure 4 (Not shown in the diagram) in the vicinity. In this embodiment, in Figure 4 In the cross section, the first end face 27d and the second end face 27e each have a straight line shape.

[0074] exist Figure 4 In the cross-section, the inner peripheral surface 27a and the first end surface 27d are interconnected by a first R-shape R1. That is, in Figure 4 In the cross-section, the corner between the inner circumferential surface 27a and the first end face 27d is rounded. In another description, in Figure 4 In the cross section, the inner circumferential surface 27a and the first end surface 27d are connected to each other by an arc shape.

[0075] exist Figure 4 In the cross-section, the first R-shape R1 is connected to the inner peripheral surface 27a through a tangent to the first R-shape R1. That is, the first R-shape R1 is smoothly connected to the inner peripheral surface 27a without any edges. Similarly, the first R-shape R1 is connected to the first end face 27d through a tangent to the first R-shape R1. That is, the first R-shape R1 is smoothly connected to the first end face 27d without any edges.

[0076] exist Figure 4 In the cross-section, the inner circumferential surface 27a and the second end surface 27e are interconnected by a second R-shape R2. That is, inFigure 4 In the cross-section, the corner between the inner circumferential surface 27a and the second end surface 27e is rounded. In another formulation, in Figure 4 In the cross section, the inner circumferential surface 27a and the second end surface 27e are connected to each other by an arc shape.

[0077] exist Figure 4 In the cross-section, the second R-shape R2 is connected to the inner peripheral surface 27a through its tangent. That is, the second R-shape R2 is smoothly connected to the inner peripheral surface 27a without any edges. Similarly, the second R-shape R2 is connected to the second end surface 27e through its tangent. That is, the second R-shape R2 is smoothly connected to the second end surface 27e without any edges.

[0078] In this embodiment, Figure 4 In the cross-section, the radius of curvature of the first R-shape R1 is more than 6% of the width w of the drive ring 27 in the axial direction. Additionally, in Figure 4 In the cross-section, the radius of curvature of the first R-shape R1 is less than 45% of the width w. Similarly, in Figure 4 In the cross-section, the radius of curvature of the second R-shape R2 is more than 6% of the width w. Additionally, in... Figure 5 In the cross section, the radius of curvature of the second R shape R2 is less than 45% of the width w.

[0079] With this structure, the inner circumferential surface 27a of the drive ring 27 includes a first R-shape R1 and a second R-shape R2 at both ends in the axial direction, thus preventing the outer surface 26d of the first protrusion 26b from contacting sharp edges. Therefore, wear on the first protrusion 26b caused by the rotation of the drive ring 27 can be reduced.

[0080] Figure 5 This is a graph showing the relationship between the dimensions of the R-shape and the surface pressure ratio. Figure 5 In this study, with the nozzle drive mechanism 20 operating under rated conditions, the surface pressure applied to the contact area between the inner circumferential surface 27a of the drive ring 27 and the outer surface 26d of the first protrusion 26b was analyzed. Furthermore, Figure 5 The relationships shown apply to the first R shape R1 and the second R shape R2, respectively.

[0081] exist Figure 5In the graph, the horizontal axis indicates the size of the R shape, specifically, the proportion (%) of the radius of curvature of the R shape with respect to the width w of the drive ring 27. The vertical axis indicates the surface pressure ratio, specifically, the ratio of the surface pressure under each condition with respect to the surface pressure applied to the drive ring 27 without the first R shape Rl and the second R shape R2. The threshold value indicates the surface pressure ratio corresponding to the plastic flow pressure of the main material used for the first protrusion 26b, such as stainless steel, for example, SUS310. Further, if the size of the nozzle drive mechanism 20 increases, the load applied to the drive ring 27 and the first protrusion 26b also increases. Therefore, it is assumed that the load applied per unit area is substantially constant regardless of the size of the nozzle drive mechanism 20.

[0082] According to Figure 4 It is known that if the size of the R shape is 6% or more of the width w, the surface pressure ratio is less than the threshold value. Therefore, if the size of the R shape is 6% or more of the width w, the plastic deformation of the outer surface 26d of the first protrusion 26b can be suppressed, and the wear of the outer surface 26d can be reduced.

[0083] Referring to Figure 6A , the present inventors found that the outer surface 26d of the first protrusion 26b is further worn, particularly in the region in contact with the corner between the inner peripheral surface 27a and the first end surface 27d of the drive ring 27 close to the connection flow path 62. This can be due to various factors. For example, by heat from the exhaust gas flowing in the connection flow path 62, the support ring 26 is more deformed in the region close to the connection flow path 62, and thus the first protrusion 26b can strongly contact the drive ring 27 in the region close to the connection flow path 62. As for other reasons, if the first protrusion 26b contacts the drive ring 27, the leading end, i.e., the free end of the first protrusion 26b can be deformed away from the drive ring 27, and thus the first protrusion 26b can strongly contact the drive ring 27 in the region close to the fixed end, i.e., the region close to the connection flow path 62. Therefore, by forming the first R shape Rl at the corner between the inner peripheral surface 27a and the first end surface 27d, the wear of the first protrusion 26b can be further reduced.

[0084] In addition, if the radius of curvature of each of the first R shape Rl and the second R shape R2 exceeds 45% of the width w of the drive ring 27, the contact region between the outer surface 26d of the first protrusion 26b and the inner peripheral surface 27a of the drive ring 27 is substantially formed in a linear shape, and the surface pressure can increase. Therefore, the radius of curvature of each of the first R shape Rl and the second R shape R2 can also be 45% or less.

[0085] For example, the drive ring 27 including the first R shape Rl and the second R shape R2 as described above can also be manufactured by barrel polishing.

[0086] Figure 6Bis a schematic cross-sectional view of the drive ring 27X after press working and before barrel polishing. Figure 6A is a schematic cross-sectional view of the drive ring 27 after barrel polishing. Figure 6B and Figure 6A respectively indicate cross sections along the axis of the turbine wheel 3.

[0087] Specifically, as shown in Figure 6B , the drive ring 27 without the first R shape R1 and the second R shape R2 is formed by press working such as blanking. In the press working, the inner periphery of the second end surface 27e is pulled in the axial direction due to the blanking, and an R shape Rx is sometimes formed at the corner between the inner peripheral surface 27a and the second end surface 27e. However, in this state, an edge Ed is formed between the inner peripheral surface 27a and the R shape Rx. In addition, the corner between the inner peripheral surface 27a and the first end surface 27d is formed to be sharp. In fact, the drive ring 27X in this state is also sometimes used in the nozzle drive mechanism 20.

[0088] However, in the present embodiment, the drive ring 27X after the press working is further polished by barrel polishing. Thus, as shown in Figure 7A , the drive ring 27 including the first R shape R1 and the second R shape R2 is formed. In other embodiments, the first R shape R1 and the second R shape R2 can also be formed in the drive ring 27 by other processing such as machining.

[0089] Figure 2 is an example of a cross-sectional view of the first protrusion 26b taken along the c-c line in Figure 7B . Figure 2 is another example of a cross-sectional view of the first protrusion 26b taken along the c-c line in Figure 7A . Figure 7B and Figure 7A respectively indicate cross sections perpendicular to the axis of the turbine wheel 3.

[0090] Referring to Figure 7A , the first protrusion 26b includes a third end surface 26e, a fourth end surface 26f, and an inner surface 26g in addition to the outer surface 26d described above.

[0091] The outer surface 26d and the inner surface 26g are located at positions opposite to each other in the radial direction. The inner surface 26g faces the radially inner side. The outer surface 26d faces the radially outer side. In the present embodiment, in the cross section of Figure 7A , the inner surface 26g and the outer surface 26d each have a circular arc shape. According to such a structure, the outer surface 26d can extend in the circumferential direction along the inner peripheral surface 27a of the drive ring 27. This contributes to reduction in the face pressure. In other embodiments, in the cross section of Figure 7AThe inner surface 26g and the outer surface 26d can also have straight line shapes in the cross section, respectively.

[0092] The third end surface 26e and the fourth end surface 26f are located at positions opposite to each other in the circumferential direction. In the present embodiment, the third end surface 26e and the fourth end surface 26f have straight line shapes in the cross section, respectively. Figure 7A

[0093] In the cross section, the outer surface 26d and the third end surface 26e are connected to each other by a third R shape R3. That is, in the cross section, a corner between the outer surface 26d and the third end surface 26e is rounded. In another expression, in the cross section, the outer surface 26d and the third end surface 26e are connected to each other by a circular arc shape. Figure 7A Figure 7A Figure 7A In the cross section, the outer surface 26d and the third end surface 26e are connected to each other by a circular arc shape.

[0094] In the cross section, the third R shape R3 is connected to the outer surface 26d by a tangent line of the third R shape R3. That is, the third R shape R3 is smoothly connected to the outer surface 26d without an edge. Similarly, the third R shape R3 is connected to the third end surface 26e by a tangent line of the third R shape R3. That is, the third R shape R3 is smoothly connected to the third end surface 26e without an edge. Figure 7A In the cross section, the outer surface 26d and the fourth end surface 26f are connected to each other by a fourth R shape R4. That is, in the cross section, a corner between the outer surface 26d and the fourth end surface 26f is rounded. In another expression, in the cross section, the outer surface 26d and the fourth end surface 26f are connected to each other by a circular arc shape.

[0095] Figure 7A In the cross section, the outer surface 26d and the fourth end surface 26f are connected to each other by a circular arc shape. Figure 7A Figure 7A In the cross section, the fourth R shape R4 is connected to the outer surface 26d by a tangent line of the fourth R shape R4. That is, the fourth R shape R4 is smoothly connected to the outer surface 26d without an edge. Similarly, the fourth R shape R4 is connected to the fourth end surface 26f by a tangent line of the fourth R shape R4. That is, the fourth R shape R4 is smoothly connected to the fourth end surface 26f without an edge.

[0096] According to such a structure, the outer surface 26d of the first protrusion 26b includes the third R shape R3 and the fourth R shape R4 at both end portions in the circumferential direction, and thus the inner peripheral surface 27a of the drive ring 27 (not illustrated in FIG. 10) can avoid contact with a sharp edge. Therefore, it is possible to reduce abrasion of the drive ring 27 caused by rotation of the drive ring 27. Figure 7A With reference to

[0097] Figure 7B

[0098] With reference to Figure 7B ​​​​​​​In this example, the outer surface 26d and the third end surface 26e are connected to each other by the third chamfer C3 instead of the third R shape R3. That is, in a cross section along the axis of the turbine wheel 3, the outer surface 26d and the third end surface 26e are connected to each other by a straight line shape. Further, the outer surface 26d and the fourth end surface 26f are connected to each other by the fourth chamfer C4 instead of the fourth R shape R4. That is, in a cross section along the axis of the turbine wheel 3, the outer surface 26d and the fourth end surface 26f are connected to each other by a straight line shape. Figure 7B In this example, the outer surface 26d and the third end surface 26e are connected to each other by the third chamfer C3 instead of the third R shape R3. That is, in a cross section along the axis of the turbine wheel 3, the outer surface 26d and the third end surface 26e are connected to each other by a straight line shape. Further, the outer surface 26d and the fourth end surface 26f are connected to each other by the fourth chamfer C4 instead of the fourth R shape R4. That is, in a cross section along the axis of the turbine wheel 3, the outer surface 26d and the fourth end surface 26f are connected to each other by a straight line shape. Figure 7A In this example, the outer surface 26d and the third end surface 26e are connected to each other by the third chamfer C3 instead of the third R shape R3. That is, in a cross section along the axis of the turbine wheel 3, the outer surface 26d and the third end surface 26e are connected to each other by a straight line shape. Further, the outer surface 26d and the fourth end surface 26f are connected to each other by the fourth chamfer C4 instead of the fourth R shape R4. That is, in a cross section along the axis of the turbine wheel 3, the outer surface 26d and the fourth end surface 26f are connected to each other by a straight line shape. ​

[0099] The supercharger TC described above includes the turbine wheel 3, the casing 1 that houses the turbine wheel 3 and includes the connection flow path 62 formed on a radially outer side of the turbine wheel 3, the plurality of rotatable nozzle vanes 24 arranged in the connection flow path 62 along a circumferential direction, the support ring 26 having a ring shape around the axis of the turbine wheel 3 and housed in the casing 1, and the drive ring 27 having a ring shape around the axis of the turbine wheel 3 and rotating around the support ring 26 to simultaneously rotate the plurality of rotatable nozzle vanes 24. The drive ring 27 includes the inner peripheral surface 27a in contact with the support ring 26, and the first end surface 27d and the second end surface 27e in the axis direction. The first end surface 27d is arranged in the vicinity of the connection flow path 62 in the axis direction with respect to the second end surface 27e. The drive ring 27 includes the first R shape R1 that connects the inner peripheral surface 27a to the first end surface 27d in a cross section along the axis of the turbine wheel 3. As described above, the present inventors found that the outer surface 26d of the support ring 26 is further worn in a region in contact with a corner portion of the drive ring 27 near the connection flow path 62, that is, a corner portion between the inner peripheral surface 27a and the first end surface 27d. According to the structure described above, the inner peripheral surface 27a of the drive ring 27 includes the first R shape R1 in the corner portion described above, and thus the outer surface 26d of the support ring 26 can avoid contact with a sharp edge. Therefore, it is possible to reduce wear of the support ring 26 caused by rotation of the drive ring 27.

[0100] Further, in the supercharger TC, the first R shape R1 is connected to the inner peripheral surface 27a by a tangent line of the first R shape R1 in the cross section described above. According to such a structure, the first R shape R1 is smoothly connected to the inner peripheral surface 27a without an edge, and thus it is possible to further reduce wear.

[0101] Further, in the supercharger TC, in the cross section described above, a radius of curvature of the first R shape R1 is 6% or more of a width w of the drive ring 27 in the axis direction. As described above, if the size of the R shape is 6% or more of the width w, it is possible to substantially suppress plastic deformation of the outer surface 26d of the support ring 26, and it is possible to further reduce wear of the outer surface 26d.

[0102] ​Further, in the supercharger TC, the first R shape R1 has a radius of curvature of 45% or less of the width w in the above-mentioned cross section. According to such a structure, it is possible to avoid the contact area between the drive ring 27 and the support ring 26 from being formed in a linear shape.

[0103] Further, in the supercharger TC, the drive ring 27 includes a second R shape R2 connecting the inner peripheral surface 27a to the second end surface 27e in the above-mentioned cross section. According to such a structure, it is possible to further reduce the abrasion of the support ring 26 caused by the rotation of the drive ring 27.

[0104] Further, in the supercharger TC, the support ring 26 includes a plurality of first protrusions 26b protruding in the axial direction and contacting the inner peripheral surface 27a of the drive ring 27, and the plurality of first protrusions 26b each include an outer surface 26d contacting the inner peripheral surface 27a of the drive ring 27, a third end surface 26e in the circumferential direction, and a fourth end surface 26f. In one example, the plurality of first protrusions 26b each include a third R shape R3 connecting the outer surface 26d to the third end surface 26e and a fourth R shape R4 connecting the outer surface 26d to the fourth end surface 26f in a cross section perpendicular to the axis of the turbine wheel 3. In another example, the plurality of first protrusions 26b each include a third chamfer C3 connecting the outer surface 26d to the third end surface 26e and a fourth chamfer C4 connecting the outer surface 26d to the fourth end surface 26f in the above-mentioned cross section. According to these structures, it is possible to reduce the abrasion of the drive ring 27 caused by the rotation of the drive ring 27.

[0105] The above describes one embodiment of the present disclosure with reference to the drawings, but the present disclosure is of course not limited to the above-described embodiment. It will be understood by those skilled in the art that various modifications or corrections are conceivable within the scope recited in the claims, and such modifications certainly fall within the technical scope of the present disclosure.

[0106] Explanation of Reference Signs

[0107] 1 Housing

[0108] 3 Turbine wheel

[0109] 24 Nozzle blade

[0110] 26 Support ring

[0111] 26b First protrusion (protrusion)

[0112] 26d Outer surface

[0113] 26e Third end surface

[0114] 26f Fourth end surface

[0115] 27 Drive ring

[0116] 27a inner peripheral surface

[0117] 27d first end surface

[0118] 27e second end surface

[0119] 62 connection flow path (annular flow path)

[0120] C3 third chamfer

[0121] C4 fourth chamfer

[0122] R1 first R shape

[0123] R2 second R shape

[0124] R3 third R shape

[0125] R4 fourth R shape

[0126] TC supercharger

[0127] W width of the drive ring in the axial direction

Claims

1. A booster, characterized in that, have: Turbine impeller; A housing that houses the turbine impeller and includes an annular flow path formed on the radially outer side of the turbine impeller; Multiple rotatable nozzle blades are arranged circumferentially along the turbine impeller in the annular flow path. A support ring having an annular shape around the axis of the turbine impeller and being housed in the housing; as well as The drive ring has an annular shape about the axis of the turbine impeller, and rotates about the support ring to cause the plurality of rotatable nozzle blades to rotate simultaneously. The drive ring includes: an inner circumferential surface that contacts the aforementioned support ring; and a first end face and a second end face in the axial direction of the aforementioned turbine impeller. The first end face is positioned near the annular flow path relative to the second end face in the axial direction. The drive ring includes a first R-shape in which the inner circumferential surface is connected to the first end face in a cross section along the axis of the turbine impeller.

2. The booster according to claim 1, characterized in that, The first R-shape is connected to the inner circumferential surface in the cross-section via a tangent to the first R-shape.

3. The booster according to claim 1, characterized in that, In the aforementioned cross-section, the radius of curvature of the aforementioned first R-shape is at least 6% of the width of the aforementioned drive ring in the aforementioned axial direction.

4. The booster according to claim 3, characterized in that, In the aforementioned cross-section, the radius of curvature of the aforementioned first R-shape is less than 45% of the aforementioned width of the aforementioned drive ring.

5. The booster according to claim 1, characterized in that, The aforementioned drive ring includes a second R-shape in the aforementioned cross-section that connects the aforementioned inner circumferential surface to the aforementioned second end face.

6. The booster according to claim 1, characterized in that, The aforementioned support ring includes a plurality of protrusions that project in the direction of the aforementioned axis and contact the aforementioned inner circumferential surface of the aforementioned drive ring. Each of the aforementioned protrusions includes an outer surface that contacts the inner circumferential surface of the drive ring, and a third end face and a fourth end face in the circumferential direction. Each of the aforementioned protrusions includes a third R-shape that connects the outer surface to the third end face in a section perpendicular to the axis of the turbine impeller, and a fourth R-shape that connects the outer surface to the fourth end face.

7. The booster according to claim 1, characterized in that, The aforementioned support ring includes a plurality of protrusions that project in the direction of the aforementioned axis and contact the aforementioned inner circumferential surface of the aforementioned drive ring. Each of the aforementioned protrusions includes an outer surface that contacts the inner circumferential surface of the drive ring, and a third end face and a fourth end face in the circumferential direction. Each of the aforementioned protrusions includes a third chamfer that connects the outer surface to the third end face in a section perpendicular to the axis of the turbine impeller, and a fourth chamfer that connects the outer surface to the fourth end face.

Images